The invention relates to a method of and a system for transmitting a high-definition television signal containing picture information which, on display, forms first picture frames at a rate of 2n frames per second, where n is a standard number of picture frames per second formed by the picture information in a standard television signal, and having a width which is wider than that of a standard aspect ratio picture frame, said high-definition television signal having a bandwidth greater than that of a standard television signal, each of said first picture frames including a single field having m sequentially scanned scanning lines, where m is a standard number of interlaced scanning lines in each picture frame formed by the picture information in said standard television signal in which said scanning lines are arranged in two interlaced fields.
One of the most disturbing characteristics of present day television is its inadequate vertical resolution as manifest on large displays by the viewers being able to discern the individual raster lines. Various systems have been proposed having an increased number of horizontal scanning lines. However, these systems are not feasible as they require an excessive amount of bandwidth (e.g. 30 MHz.). Other systems have been proposed in which additional lines are transmitted over a separate channel or are generated in the television receiver by interpolation.
One thing in common with all the above systems is an increase in cost to both the broadcaster as well as the consumer. This brings into play the marketing of the new television system. It has been shown that increased resolution alone may not be sufficient to offset the increase in cost of a television receiver to the consumer.
In response to this marketing problem, some systems propose increasing the width of the displayed picture by correspondingly increasing the aspect ratio by 33.3%, from a standard aspect ratio of 4:3 to 51/3:3, combined with increasing the number of scanning lines in each picture frame and increasing the bandwidth of the luminance in the television signal by at least two times.
All of these increases necessitate the transmission of the television signal over at least two separate channels, in which a first of the channels carries a first transmission signal which is compatible with standard television receivers, and a second of the channels carries a second transmission signal which, when combined with the first transmission signal, forms a television signal which corresponds substantially to the high-definition television signal.
Each of these systems include at least one frame store at the receiver capable of storing at least one picture frame of the television signal which significantly adds to the cost of the receiver.